Gas prices rose just half a cent a gallon in the past two weeks, continuing an unusual 20-week trend of mostly steady prices, an industry analyst said today.

The average price for gas nationwide, including all grades and taxes, was about $1.46 a gallon on Friday, according to the Lundberg survey of 8,000 stations.

That was up 50 cents per gallon from August ninth. Analyst Trilby Lundberg says prices have shown little change since early April, when a gallon of gas also cost about $1.46.

Lundberg says there was no midsummer spike in prices this year because of stability in crude oil prices and at U.S. refineries.